1. Field of the Invention
The present invention relates generally to oral syringe packaging equipment and more specifically to a fully automated system for preparing patient-specific doses of selected pharmaceutical liquid medication for administration by oral syringe on a patient specific, just-in-time, medication error-free, and cost effective basis, for use in a hospital pharmacy.
2. Description of the Background
Oral syringes are well known instruments in the medical fields and are used to administer liquid medicine into the mouth, typically for infants/children and uncooperative or geriatric adults, as an alternative to pills which can present a choking hazard or be expectorated. The oral syringe directs liquid medicine to the back of the throat prompting a swallowing response. Injectable syringes, on the other hand, are used to administer medication into the body by injecting its contents through the skin. Injectable syringes utilize a needle on the tip of the syringe. Injectable syringes must be manufactured and packaged in a sterile environment. Research has shown that the potential for adverse drug events within the pediatric inpatient population is about three times as high as among hospitalized adults. See, Joint Commission, Preventing Pediatric Medication Errors, Issue 39 (2008). According to the Commission Report, the most common types of harmful pediatric medication errors were improper dose/quantity (37.5 percent) and unauthorized/wrong drug (13.7 percent), followed by improper preparation or dosage form. Oral syringes help to minimize these problems and are considered the gold standard for delivering medicine to children.
Oral syringes comprise a simple piston pump with a plunger that fits tightly in one end of a cylindrical tube (the barrel) and can be pushed or pulled along inside the barrel to create negative or positive relative pressure within the barrel that causes the syringe to take in or expel a liquid or gas through an orifice at the opposing end of the barrel. The barrel of an oral syringe is typically made of plastic and is at least partially transparent along its length with graduated markings to indicate the volume of fluid in the syringe based on the position of the plunger. Oral syringes come in a wide range of sizes, some with nozzle located centrally and some offset from center, and this variability makes it difficult to automate the filing process. Oral syringes are commonly marked in units of milliliters and come in standard sizes ranging from 0.5 to 60 milliliters. An annular flange partially or fully encircling the outside surface of the barrel is typically provided to facilitate compression of the plunger into the barrel. The plunger is also typically plastic as this provides a good seal within the barrel and is inexpensive to produce so as to be disposable, reducing the risk of contamination or transmission of spreading disease.
Pharmacies at in-patient medical facilities and other medical institutions fill a large number of prescriptions on a daily basis including prescriptions for liquid or compounded suspension medicines to be administered by oral syringe and must do so accurately for medical safety reasons. The volume of an oral pediatric prescription's dose is determined by the child's weight. This makes it impractical to stock pre-filled syringes due to the wide range of fill volumes required. As a result, pediatric oral liquid doses are prepared in the hospital pharmacy on a patient-specific, just-in-time basis. The process of filling numerous, variously sized single dose prescriptions for delivery by oral syringe is time consuming, labor intensive and prone to human error. Moreover, the manual manipulation of all the myriad prescription bottles as well as variously-sized oral syringes can lead to injury such as carpal tunnel syndrome. To insure that the medication is packaged error-free, the pharmacy technician must make sure that: (1) the syringe contains the correct medication; (2) the syringe contains the correct amount of medication: (3) the syringe is capped correctly; (4) the medication has not expired; (5) the medication has not been recalled; (6) the medication, when required, is shaken; (7) the medication, when required, has been properly refrigerated; (8) the medication, when required, has been properly protected from exposure to light; (9) the information on the syringe label is correct: (10) the syringe is placed into the correct bag; (11) the information on the bag containing the syringe is correct; (12) the bag is properly sealed; and (13) the syringe is protected from cross contamination from other medications. The process typically requires a pharmacist or pharmacy technician to retrieve the correct medication from a storage cabinet or refrigerated storage area. The liquid medications are typically stored in a container sealed with a safety cap or seal. After confirming the contents of the retrieved container and shaking the medication (if necessary), the technician opens the cap and inserts the tip of an oral syringe into the container, withdrawing the plunger to draw the medication into the barrel of the syringe. After filling with a proper amount, the tip of the syringe is covered with a cap for transport to the patient, and the syringe is labeled to indicate its content, the intended recipient, and then bagged. Prior to administering the dose, the nurse can determine the amount of the dose by observing where the tip of the plunger or piston is located in the barrel. Most oral syringes are marked for measuring the dose in milliliters (mL). Oral syringes are relatively inexpensive and disposable.
Currently, the degree of automation in the hospital pharmacy for the packaging of oral syringes is very limited. Islands of automation exist, such as automatic labeling of the syringe and bagging of the filled and capped syringe. However, the filling and capping are done manually. Scanners, cameras, bar code readers and track and trace technology have not been applied on an integrated, comprehensive basis for the packaging of oral syringes in the hospital pharmacy. The potential to reduce medication errors using this technology is significant. Automated systems have been developed by Baxa, Inc., For Health Technologies, Inc., Intelligent Hospital Systems and others for the automated filling of injectable syringes.
For example, U.S. Pat. Nos. 6,991,002, 7,017,622, 7,631,475 and 6,976,349 are all drawn to automated removal of a tip cap from an empty syringe, placing the tip cap at a remote location, and replacing the tip cap on a filled syringe. U.S. Pat. Nos. 7,117,902 and 7,240,699 are drawn to automated transfer of a drug vial from storage to a fill station. U.S. Pat. No. 5,884,457 shows a method and apparatus for filling injectable syringes using a pump connected by hose to a fluid source. U.S. Pat. No. 7,610,115 and Application 20100017031 show an Automated Pharmacy Admixture System (APAS). US Application 20090067973 shows a gripper device for handling syringes with tapered or angled gripper fingers. U.S. Pat. No. 7,343,943 shows a medication dose underfill detection system. U.S. Pat. No. 7,260,447 shows an automated system for fulfilling pharmaceutical prescriptions. U.S. Pat. No. 7,681,606 shows an automated system and process for filling injectable syringes of multiple sizes. U.S. Pat. No. 6,877,530 shows an automated means for withdrawing a syringe plunger. U.S. Pat. No. 5,692,640 shows a system for establishing and maintaining the identity of medication in a vial using preprinted, pressure sensitive, syringe labels.
The foregoing references are generally suitable for packaging injectable syringes. The packaging process required for injectable syringes is significantly different than that for oral syringes. Injectable syringes must be packaged in a sterile environment as the medication is injected into the body. This requirement adds cost and complexity to the machine. Injectable medications when packaged on a just-in-time basis, as with the Baxa, For Health Technologies, and Intelligent Hospital System machines, must typically be prepared by the machine before the medication is filled into the syringe. The medication preparation process involves diluting the medication or reconstituting the medication from a powder with water. This process adds expense and slows down the packaging process as well. The Intelligent Hospital Systems syringe packaging system is designed to be used to package cytotoxic medications which are hazardous. To avoid harm to the operator, this machine uses a robot located within an isolator barrier at considerable cost. The Baxa, For Health Technologies, and Intelligent Hospital System machines require the use of expensive disposable product contact parts when a different medication is to be filled. The foregoing machines are not suitable for packaging oral syringes due to their capital cost, complexity, slow production rates, inability to handle oral medication containers, and the requirement of expensive disposable contact parts. Consequently, existing automation does not address the needs of medical institutions desiring an affordable pharmacy automation system for patient safety, prescription tracking and improved productivity. The present invention was developed to fill this void.
Oral syringes are manufactured in a variety of sizes with differing tip and plunger configurations. Moreover, oral medications are commonly provided in bulk form in variously-sized bottles or containers having threaded screw caps that must be removed and replaced between uses. For example, U.S. Pat. No. 4,493,348 shows a method and apparatus in which oral syringes can be filled using a screw-on adapter cap 12 for connecting the bulk medicine container 10 and a syringe 14 so that the liquid medication can be transferred from the bulk container 10 into the syringe barrel 20. The syringe is inserted into a nozzle 88 of the adapter cap 12 and displaces a detent valve 92 (see FIG. 6) that allows medicine to flow through the nozzle 88 into the syringe. When not in use the nozzle 88 may be closed off by a plug 50 attached to a tether 48. The adapter cap 12 is well-suited for manual filling of oral syringes but is not suitable for automated filling. The design of the cap 12 is specific to only one size of bulk medicine container and one size syringe nozzle. The variety of bulk container sizes and syringe sizes with differing tip and plunger configurations would require a large inventory of adapter caps 12 in an automated environment. Given the diversity of oral syringes and medicine containers available, any fully automated system will need sufficient dexterity to manipulate all the myriad prescription bottles containing the pharmaceuticals to be dispensed as well as variously-sized oral syringes, bringing them together in a controlled environment to quickly and accurately fill and label each syringe and to verify its work as it proceeds in order to avoid errors in the process. Such a system would need to be reliably constructed so as to minimize downtime, quickly take and fill orders, be easy to clean and capable of maintaining an environment free from cross contamination. Such a system would also need to be able to interact with a human operator throughout the operation.
Additionally, in-patient medical facilities such as hospitals are moving toward electronic prescription (e-prescription) systems which use computer systems to create, modify, review, and/or transmit medication prescriptions from the healthcare provider to the pharmacy. While e-prescribing improves patient safety and saves money by eliminating the inefficiencies and inaccuracies of the manual, handwritten prescription process, any syringe fill automation system suitable for use in a hospital setting must interface with an existing e-prescription system (which records and transmits prescriptions to the pharmacy), and must be capable of filling prescription orders in a just-in-time environment.
The present inventors herein provide a fully-automated system suitable for use in a hospital setting for filling patient-specific doses of liquid medications to be administered by oral syringes on a patient specific, just-in-time, medication error-free, and cost effective basis. The system enables hospital pharmacists to simplify and streamline their task, increasing the number of prescriptions that can be filled in a day while avoiding the risk of human error and the risk of carpal tunnel syndrome to the pharmacist or technician, improving both patient and pharmacist/technician safety and care. Direct supervision of the technician by the pharmacist is reduced due to the inspection/track and trace system that minimizes the opportunity for error.